Did you know the smartphone in your pocket might be the dirtiest thing on you at any given moment? An oft-cited report from the London School of Hygiene and Tropical Medicine found that 92 percent of the smartphones it tested were covered with bacteria. Worse, 16 percent of the phones it examined had E. coli present. Another study says smartphone displays can be dirtier than a toilet seat. Yuck! Here's how to keep your phone clean.